Where oil-filled capacitors in high power VLF transmitters, such capacitors are prone to catastrophic failure due to breakdown of the oil. Such breakdown is induced by decomposition of the oil. The age/use induced change in the dielectric properties then should be determined early enough so that the oil can be changed before catastrophic damage sets in. Technicques in use at this time employ cumbersome and relatively inaccurate methods for determining the quality of dielectric fluids such as petroleum-derived oils. The Perelli test measures the quantity of hydrogen and hydrocarbon gases evolved or absorbed under high electric field stress. As discussed by A. A. Zacky and I. Y. Megahed, Transaction Electrical Insulation, EI-7, 145 (1972). Another technique is one which determines the fractional content of unsaturated aromatics present in the oil. Such aromatics of which benzene, naphathalene or anthracene are typical, tend to absorb hydrogen, ethane, propane, etc., preventing the formation of gas bubbles. Such bubbles tend to ionize in electric fields of 30 to 50 kV/cm initiating the decomposition of the oil and ultimately its catastrophic breakdown. Nuclear magnetic resonance and proton magentic resonance, techniques have been employed to determine the concentration of unsaturated aromatics in commercially available oils. The apparatus required for these tests is expensive, bulky and not suitable for on-line monitoring of the properties of insulating oils.